In our previous post we had hinted at a cataclysmic event which was shortly to take place which we believe would rectify (that is for the time being) the runaway greenhouse effect that was overtaking our newly forming world. Now as stated before some have suggested that the early primordial atmosphere could not have been as thick as we have suggested due to its close proximity to the sun and its solar winds, note the following remarks as taken from “Early Earth’s Magnetic Field Was a Weakling” by Andrea Thompson, http://www.space.com/8006-early-earth-magnetic-field-weakling.html)
“A recent study suggests that “the protective magnetic field shrouding the early Earth was likely only half as strong as it is today.” In truth little is known about the magnetic field as it existed just after the Earth formed, around 4.5 billion years ago. It is the magnetic field which keeps solar particles from eating away at the molecules in the Earth’s atmosphere.
In the past, not only was the earth’s magnetic field weaker, the sun was likely rotating more rapidly and therefore spinning off a stronger solar wind and a magnetopause that was likely much closer to Earth. Today it is at a distance of about 10.7 Earth radii, but then it would likely have been around 5 Earth radii out (Earth’s average radius is about 4,960 miles, or 6,370 km).”
“That means that the particles streaming out of the sun were much more likely to reach Earth. The implication of that situation is that “it’s very likely the solar wind was removing volatile molecules, like hydrogen, from the atmosphere at a much greater rate than we’re losing them today… the loss of hydrogen implies a loss of water as well.
In turn, if a lot of water was stripped away early in Earth’s history, to get the amount of water that we have now (not to mention the amount that completely covered the earth at the beginning of day one of creation), the planet must have started “with either a fairly robust inventory of water,” and or it was possibly being continuously replenished by further impacts from comets and asteroids, as well as small planetesimals.”
Mars minuscule atmosphere is one example of what happens when a planet lacks a significant magnetic field to protect itself from the sun’s radiation. However as someone said, Observation, the final judge of scientific truth proves some things are not always as expected. As discussed in our previous post Venus which completely lacks a magnetic field, at least none which has been discovered as of yet defies this assumption, and retains its atmosphere.
AS FOR THE MOON
Pictured above is a depiction of a small planetesimal possibly Theia on approach impacting the early earth’s atmosphere.
“According to another study, the moon came into existence after several planet-size space bodies (planetesimals) smashed into the nascent Earth one after the other, with the final one actually forming our satellite, while several impacts repeatedly blew off our planet’s atmosphere.
Until now, scientists thought it was unlikely that the early Earth could lose its atmosphere because of a giant moon-forming impact. But the new research, based on recent studies showing that at its infancy our planet had magma oceans and was spinning so rapidly that a day was only two or three hours long, argues that this may have been possible.”
“Research conducted by planetary scientist Sarah Stewart, a professor at Harvard University along with several of her fellow colleagues argued that the moon is actually a giant merger of bits and pieces of our own planet, partially destroyed by a catastrophic collision with a space body 4.5 billion years ago.
Back then, the Earth had a two- or three-hour day, she said, and the impact made it throw off enough material to coalesce into what became our satellite, making it the Earth’s geochemical twin. This ultra-rapid spin is one of the important conditions necessary to make the atmospheric loss theory work, Stewart said. The other criterion is the presence of terrestrial magma oceans — and this hypothesis has now got support thanks to new data obtained from volcanoes.
Two of her colleagues, who presented their work at the 44th Lunar and Planetary Science Conference in March, sampled elements from volcanoes in Iceland, which have rocks that are among the oldest on Earth and thus retain the geo-chemical signatures of the Earth’s so-called lower-most mantle, closest to the planet’s core. They also looked at elements found in volcanoes that sample the upper mantle, such as mid-ocean ridge basalt’s at the bottom of the Atlantic. They found that elements in the deep mantle that retain a very ancient chemistry, from the times of the Earth’s formation, are very different from those in the upper mantle we see today.
In particular, the presence of two noble gases, helium and neon, is very different today from what it used to be, Stewart said. Both these gases are very rare on today’s Earth, but they are found in the solar system in abundance. And as “documented” by the deep Earth, when our planet was just forming it contained much more helium and neon as well.
“The implication is that [the lower-most mantle] hasn’t been completely overprinted by subsequent evolution, and it’s helping us pinpoint events that had to happen to lead to the planet we see today.
So how and why did these gases disappear?
While helium is not gravitationally bound to the Earth, neon is, and it needs a powerful “kick” to escape. “For such a dramatic change to happen you can’t do that with just open loss off the top (as suggested in our first study concerning the early earth’s weak magnetic field) — instead, you need to eject the whole atmosphere in a catastrophic type of event, a giant impact.
Besides atmospheric loss caused by impacts that melt all rock to create magma oceans, to get to the present-day neon-to-helium ratio Earth would have to suffer multiple impacts. In other words, the Earth probably (formed and) lost its primordial atmosphere multiple times, and the magma oceans were melting more than once. The final impact, led to the creation of the moon, and resulted in the ratio of the gases we have today. “One single impact is not sufficient, there had to be at least two, probably more, to make that work.”
The idea that stages of Earth’s growth are recorded in chemistry is relatively new. Previously, researchers argued that during our planet’s formation (known as accretion) with a moon-forming impact, the proto-Earth was melted and mixed to the point that it “forgot” its growth — all the data was erased. “But now what we’ve learned is that data wasn’t erased, and it’s exciting because now we have clues to the stages of growth,” Stewart said. She added that the next step would be to calculate exactly under what impact conditions the early atmosphere actually might have been blown off.
But if the early atmosphere disappeared due to an impact, how did the Earth get its atmosphere back and how did it finally evolve into the one we have today?
“The currently accepted idea for how the moon was formed involves the impact or accretion of a Mars-size object with or by the proto-earth. When two objects of this size collide, large amounts of heat are generated, of which quite a lot is retained. (The amount of heat that can arise through simple accretionary processes, bringing small bodies together to form the proto-earth, is large: on the order of 10,000 kelvins about 18,000 degrees Fahrenheit). This single episode could have largely melted the outermost several thousand kilometers of the planet…In other words there was no shortage of heat in the early earth, the planet’s inability to cool off quickly would once again result in out-gassing and in the production of another primordial atmosphere similar to the last.”
“The Giant Impactor Theory (sometimes called The Ejected Ring Theory): proposes that a planetesimal (or small planet) the size of Mars struck the Earth just after the formation of the solar system, ejecting large volumes of heated material from the outer layers of both objects. A disk of orbiting material was formed, and this matter eventually stuck together to form the Moon in orbit around the Earth. This theory can explain why the Moon is made mostly of rock and how the rock was excessively heated. Furthermore, we see evidence in many places in the solar system that such collisions were common late in the formative stages of the solar system.”
Stewart says that after the last giant smashup that finally formed the moon, the Earth continued to form, accreting planetesimals — mountain-size space rocks that stuck to it, making it bigger. “These planetesimals delivered some of Earth’s *volatiles,” she says, eventually bringing the atmosphere to the state it is in today. Volatiles are elements able to escape very easily.
Ian Crawford of Birkberk College, University of London, who was not involved in the study, said that the theory sounded plausible “because multiple impacts are expected to happen in the context we think the solar system was put together.” “It’s true that each time you have a giant impact you expect a magma ocean to form. And the early planets are expected to have a transient atmosphere, so it is possible that the atmosphere would be released if the magma ocean solidified.”
*In planetary science, volatiles are the group of chemical elements and chemical compounds with low boiling points that are associated with a planet or moon’s crust or atmosphere. Examples include nitrogen, water, carbon dioxide, ammonia, hydrogen, methane and sulfur dioxide.
(Giant Impact That Formed the Moon Blew off Earth’s Atmosphere by Katia Moskvitch, http://www.space.com/23031-moon-origin-impact-earth-atmosphere.html)
Returning once again to our previous question, if the early atmosphere disappeared due to an impact, how did the Earth get its atmosphere back and how did it finally evolve into the one we have today? As stated the processes which created the previous atmospheres would once again begin anew, viz. outgassing’s, volcanic activity, impacts and etc. in fact not long after the moons formation another (hypothesized) cataclysmic event which was taking place millions of miles from earth would have a direct (and beneficial) affect upon the earth.
“About 4 to 3.8 billion years ago a period of intense comet and asteroid bombardment is thought to have peppered all the planets including the Earth. Many of the numerous craters found on the Moon and other bodies in the Solar System record this event. One theory holds that a gravitational surge caused by the orbital interaction of Jupiter and Saturn sent Neptune careening into the ring of comets in the outer Solar System. The disrupted comets were sent in all directions and collided with the planets. These water-rich objects may have provided much of the water in the Earth’s oceans. The record of this event is all but lost on the Earth because our planet’s tectonic plate system and active erosion ensure that the surface is constantly renewed.” (“The Late Heavy Bombardment Ends”, http://www.bbc.co.uk/science/earth/earth_timeline/late_heavy_bombardment)
With these continuous disruptions and impacts the heat generated by the earth would once again turn most of the volatile elements to a gaseous state which would then begin to form a thick canopy of clouds about the earth, only this time having acquired the added mass and cores of the various planetesimals especially the last great impact from Theia the earth’s gravitational as well as its magnetic field would be greatly increased the latter protecting it further from the sun’s solar winds.
“During the igneous (Azoic) period those vapors coming closer to the earth, and being drawn by gravity, were still held off the surface by great heat, but as the earth cooled, and these vapors were allowed to condense, the masses increased in weight and there would be falls from the upper masses to the cooling surface. Undoubtedly at first the water was changed to steam and returned to the atmosphere. Deluge after deluge would follow from the enshrouding mass, and slowly the earth’s surface became plastic, depressing under impact and accumulations here, with resulting rises over there, and liquids flowing into the depressions. Slowly the plastic condition firmed until the surface could support the further deluges from aerial sources, and the water would remain to collect in the lower depressions (Most likely as boiling caldrons).”
One after another these were precipitated upon the earth’s surface. These deluges from descending “rings“ would naturally reach the earth from the direction of the two magnetic poles, where there would be least resistance, because farthest from the equator, the center of the centrifugal force of the earth’s motion.
The breaking down of these “rings,” long periods apart, furnished numerous deluges (floods), and piled strata upon strata over the earth’s surface. The rush of waters from the poles toward the equator would distribute variously the sand and mud and minerals, the water strongly mineralized thus covering the entire surface of the earth, just as described at the beginning of the narrative of Genesis. (Compare Gen 1:2 and 1:9)
In our next post we will jump ahead only God knows how many millions of years to Day One of the creation.